1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming method, and an image forming program. In particular, the present invention relates to an image forming apparatus, an image forming method, and an image forming program which record an image with recording heads that record dots corresponding to pixels of image data by discharging ink droplets and discharge, in correspondence to the dots, an aggregating liquid that causes color material in the ink to aggregate.
2. Description of the Related Art
Conventionally, image forming apparatus such as inkjet recording apparatus have been known which record dots corresponding to pixels of image data by discharging ink droplets from plural nozzles.
Image forming apparatus have been proposed which, in order to obtain excellent image quality, prevent ink bleeding by discharging an aggregating liquid that causes the color material to aggregate and then discharging the ink droplets over the corresponding dots (e.g., see Japanese Patent Application Laid-Open Publication (JP-A) Nos. 2002-67296, 2002-67297 and 2004-122534).
In the technologies disclosed in JP-A Nos. 2002-67296, 2002-67297 and 2004-122534, the occurrence of stripes resulting from the discharge of ink droplets from defective nozzles, through which it is difficult to discharge ink droplets in a normal discharge amount or in a normal direction, is suppressed. Thus, the aggregating liquid is not discharged to dots recorded by nozzles in the vicinity of the defective nozzles, and the aggregating liquid is discharged to dots recorded by normal nozzles outside the vicinity of the defective nozzles. By configuring the image forming apparatus in this manner, bleeding occurs only in the dots in the vicinity of generated stripes, and the occurrence of stripes can be suppressed.
Also, in order to suppress the occurrence of stripes, the gradation value of the pixels recorded by the nozzles in the vicinity of the defective nozzles is raised and the size of the dots is increased, whereby the occurrence of stripes is suppressed.
However, in these conventional technologies, the aggregating liquid is not discharged to dots recorded by nozzles in the vicinity of the defective nozzles, and the aggregating liquid is discharged to dots recorded by normal nozzles outside the vicinity of the defective nozzles. Thus, regions in which the aggregating liquid has been discharged and regions in which the aggregating liquid has not been discharged occur in the recorded image. When the aggregating liquid is discharged in correspondence to the recorded dots, the ink aggregates due to the effect of the aggregating liquid and the dots become smaller. Thus, there has been the problem that if the aggregating liquid is discharged in different amounts, concentration unevenness and color unevenness occur, which triggers image quality deterioration.